Most of the major cities in the world are coastal cities. This is a natural outcome of the needs ... more Most of the major cities in the world are coastal cities. This is a natural outcome of the needs of human civilization. Some of the mentioned needs are transporting goods (shipping in literal means) and resources such as fish. On the other hand, wind and solar energy systems are usually built on arid land, away from settlements. Since there is an inverse relation between the size of a settlement and the aridness of a field, renewable energy systems, particularly wind and solar, are far from major settlements and industrial facilities. This creates and increases transfer/transmit and storage duties. Accordingly, additional costs arise. The additional costs and hardship undermine the transition to a carbon dioxide neutral circular sustainable life. Another thing about the location of renewables on land is that transmitting generated energy may not be possible at all. Consequently, offshore renewable energy systems are being studied and also applied. In the present work, we review the concurrent literature about offshore floating wind turbines, present an idea on them, and lay out basic equations for evaluating the idea based on economics and physics.
Arrays of offshore renewables are being studied by academia to justify them economically in real-... more Arrays of offshore renewables are being studied by academia to justify them economically in real-world applications by private sector entities. Offshore renewables' initial and levelized costs are significantly higher than their on-land counterparts. Therefore, energy density per unit area should be dramatically increased and/or cost lowered. However, concurrent knowledge of offshore industries other than renewable energy, such as fish farms, offshore oil platforms, and marine shipping, implies that lowering costs will not be sufficient. In order to increase the energy density per unit area, multiple offshore renewable energy systems relying on different physics should be combined in threedimensional space, thus creating an array. Also, systems and structures of other marine industries can be included in the concept to benefit from their readily present infrastructure. Such arrays are the subject of scientific and engineering investigation and assessment since hydrodynamics, aerodynamics, mechanics, and economics are involved. The topic is highly multidisciplinary. In this work, we reflect on the present situation and project future aspects.
To assess and forecast the operational performance of a modified car seat for thermal management ... more To assess and forecast the operational performance of a modified car seat for thermal management using an air conditioning system, statistical and machine learning (ML) models were used. By extending evaporator/condenser coils beneath the back and cushion surfaces of the car seat and using operational data on the HVAC system, such as seat temperature readings, an interval of operation was gathered. Using a data mining approach, statistically relevant factors and varying the compressor speed from 500 to 1600 rpm under various scenarios to model the system were selected. Utilizing key feature variables, our data-driven approach yielded predictions with favorable accuracy for the Coefficient of Performance (COP) of the HVAC system. By using the Akaike Information Criterion (AIC) to improve the Linear Regression (LR) model, the Root Mean Square Error (RMSE) dropped to 0.20, the Mean Absolute Error (MAE) dropped to 0.16, and the Coefficient of Determination (R 2) increased to 98 %. The Random Forest (RF) model, optimized with hyperparameters, demonstrated moderate predictive capability, with RMSE (0.52), MAE (0.37), and R 2 (94 %). Furthermore, polynomial feature augmentation, individual and combined predictor analysis, and iterative predictor combinations all improved predictive accuracy. Detailed information on the algorithms was given for the sake of other researchers.
Journal of the Faculty of Engineering and Architecture of Gazi University, 2024
Almond kernel, with a continuously increasing consumption, and is also important for our country,... more Almond kernel, with a continuously increasing consumption, and is also important for our country, is a valuable agricultural product. Its production yields the hard shell as a by-product. The shell and the kernel have approximately the same weight. However, the shell is usually burned, or occasionally ground for use in the cosmetic industry or filters. Almond shell is a porous, hard, lignocellulosic, and a renewable resource. Particleboard industry is considered for sustainable, higher value-added, and environmentally lower-impact use of this resource. For this purpose, a detailed literature review was conducted, and the reviewed studies were compiled and summarized. The literature review reveals numerous studies on the re-evaluation of shells of hard-shell nuts as materials for various industrial sectors. However, studies on almond shells are limited in number. After the literature review and conceptualization stages, particleboards with different densities and almond shell contents were produced using almond shell particles. The thermal conductivities of the boards were determined experimentally. The thermal conductivity value increases with the increase in board density. The almond shell content, however, exhibits different effects depending on the board densities. The smallest thermal conductivity value obtained in the study was 0.07 W/mꞏK, while the highest value was found to be 0.19 W/mꞏK. Although the study was conducted with a constant temperature difference, the thermal conductivity value increases with increasing temperature values.
Kahramanmaras Sutcu Imam University Journal of Engineering Sciences, 2023
In this study, the air flow resistance acting on scaled agricultural tractor models using a wind ... more In this study, the air flow resistance acting on scaled agricultural tractor models using a wind tunnel was determined experimentally. Tractor models have the same shape, but three different designs were tried on the operator platform section. These are the platform surrounded by the cab, the sunshade platform and the platform with the protection bar to protect the user in case of overturning. Thus, depending on the design of the user section, the air resistance changes that the tractors are exposed to in on-road transportation are determined experimentally for the first time. Tractor models used in the wind tunnel were prepared in a ratio of 1:13 according to geometric similarity principles. In wind tunnel tests, kinematic and dynamic similarity cannot be achieved, but Reynolds number independence can be obtained. A Reynolds number range was surveyed by performing experiments at different air velocities in the wind tunnel air flow rate range. In this range, the aerodynamic resistance forces acting on the models and the air flow-induced pressure distributions in the symmetry axis of the tractors were measured. Dimensionless aerodynamic drag coefficient and pressure coefficient values were calculated from the measurements obtained. According to the calculations, the use of the cabin increases the aerodynamic resistance in the range of 3-15%. While the percentage of resistance increase due to cabin usage is high at low speeds, it decreases at high speeds. As a result of the use of the cabin, the tractor front projection area perpendicular to the flow increases. However, the increase in aerodynamic drag is one order lower than the increase in the frontal projection area. Considering the benefits of cabin use in terms of occupational safety, it is understood that the increase in aerodynamic resistance due to cabin use is an acceptable cost. It is expected that the results of the study will contribute to the separation of energy consumption in on-road transportation with agricultural tractors.
Süleyman Demirel University Journal of Natural and Applied Sciences, 2023
In the trials of the present work, a double-axle trailer with a carrying capacity of 6 tons and a... more In the trials of the present work, a double-axle trailer with a carrying capacity of 6 tons and a hydraulically effective mechanical brake were used as a tractor towed car. There is a hydraulic brake system on each axle of the agricultural trailer. In order to separate the brake system on the axles from each other, a hydraulic mechanically controlled 2/2 directional control valve was mounted on both hydraulic brake system inlets. The study was carried out at constant speed (25 km h-1), on stabilized road conditions, with 4 different braking modes and 4 different trailer loads. On stabilized ground, the braking acceleration (deceleration) of the tractor (without trailer) is 5.51 m s-2. The braking acceleration of the combination is 2.15 m s-2 under the condition that the trailer's carrying capacity was 30% more loaded and without brakes, and the braking acceleration of the combination was 3.26 m s-2 when braking on both axles (4 wheels). The deceleration of the combination was above 3.5 m s-2 under the condition of braking on both axles at the rated load of the agricultural trailer, while it was below the standard value in other braking approaches.
Journal of Engineering Science and Technology, 2022
Data reduction and mathematical analysis are always an important part of heat transfer related st... more Data reduction and mathematical analysis are always an important part of heat transfer related studies. Regression curve (RCF) and Artificial Neural Network (ANN) fitting methods are used extensively and regarded as reliable tools for this purpose. ANN and RCF approaches are used to predict the Nusselt number (Nu), and Darcy friction factor (f) based upon a single input, namely, the Reynolds number (Re) varying from 2.3×10 3 to 52×10 3. Experimental results from a previous comprehensive study on forced thermal convection through a hexagonal duct was used to develop models and test the efficacy of the methods. Several ANN architectures, hyperparameter values and RCF functions were tested. Normalized and non-normalized datasets were considered. Models were compared with each other by means of statistical indicators. Therefore, this work is distinguished from the literature by its experimental data driven assessment and comparison between RCFs and ANNs. Additionally, single input and double output design is very scarce in the literature. The results show that the regression schemes based upon RCF are sufficient and accurate for predicting Nu and f, and the trend associated with the variation to Re is captured. The best single output ANN yields better accuracy; but the best double output ANN is unable to capture the expected trend between Re and the targeted responses. In terms of correlation coefficients, 0.98-0.99 is possible for RCFs and 0.99 for ANNs when normalization is done. Normalization becomes prominent as neuron number increases. As a conclusion, regression is preferred over ANN for a single input relationship between Nu and f to Re for hexagonal duct flow and heat transfer. An ANN's worth will only potentially be seen if more inputs; e.g., geometrical factors such as the aspect ratio, surface roughness, ambient temperature, duct material and relative wall thickness, among others, are included.
5. Internatinonal Conference on Materials Science, Mechanical and Automotive Engineerings and Technology (IMSMATEC’22), 2022
Production of almonds is increasing in a direct proportion to the increase in almond consumption ... more Production of almonds is increasing in a direct proportion to the increase in almond consumption of the world population. However, almond shells emerge as a byproduct since approximately half of the almond mass is the shell mass. Besides aiming financial gain, additional parameters should be considered due to sustainability issues and environmental concerns. Therefore, we are searching for alternative ways of almond shell utilization. Moisture value, porous structure, strength, and thermal conductivity of almond shells have a potential in respect of insulation purposes. In this work, particle boards from almond shell particles are investigated in terms of sound absorption and transmission properties. Experimental examination is utilized. In the measurements, transmission loss value can reach to 78 dB levels, making the boards a significant candidate for insulation purposes. Also, almond shell particle amount in the particle boards and variations in particle board densities greatly affect sound insulation properties of the boards.
New generation agricultural tractors contribute to transportation by increased travel speeds. The... more New generation agricultural tractors contribute to transportation by increased travel speeds. There is not any available aerodynamic data on authentic agricultural tractor form. On-road transportation by tractors is between 8 to 30% of their operational time. In this work, two agricultural tractors are modelled via computational fluid dynamics for nine different speeds to determine aerodynamic resistances. Corresponding speeds are 10 to 80 km/h with 10 km/h increments and additionally 5 km/h. Reynolds number changes between 1.6×105 and 2.98×106. The characteristic lengths are taken as the square root of the streamwise projected area of the tractor geometries. Aerodynamic forces exerted on the tractors change between 3 N to 746 N. The calculated drag coefficients are found as independent from Reynolds number and are 0.6 and 0.78 for the two different types of driver compartments. Constant speed travel scenarios are analysed. The approximated aerodynamic related fuel consumptions for ...
Karabakh III. International Congress of Applied Sciences "Year Of Shusha- 2022", 2022
Almond shell is a ligneous byproduct of almond fruit production process. This byproduct is usuall... more Almond shell is a ligneous byproduct of almond fruit production process. This byproduct is usually used as solid mass fuel. Almond shell as one of the lignocellulosic origin resources is thought to be evaluated as an alternative constituent in particle board production instead of burning it as a solid biomass fuel, in order to obtain more economical benefit. In this work, almond shells from almond fruit production process were acquired and they were grinded to make them suitable for particle board production. After the grinding process, particles sizes changing between 0.4 mm and 3.4 mm were obtained. Particle board production was realized by mixing those particles with black pine chips in different ratios. Urea formaldehyde was used as binder. Additionally, ammonium sulphate was utilized in order to harden the binder. Particle boards were obtained in laboratory conditions by proper compression pressure and temperature values for particle board production. Some particular physical and mechanical tests were done for the produced boards after climatization process. Density, thickness swelling, and water absorption amount values of the physical properties were calculated after submerging boards into water for 2 hours. In terms of mechanical properties, bending resistance and elasticity modulus, bending stress, and force values depending on the deflection were calculated. According to the obtained results, effects of almond shell and black pine particle ratios on physical and mechanical properties are examined. Additionally, mechanical, and physical properties of particle boards that were produced in different densities are investigated. At the end of the study, it is determined that increase in almond shell particle amount in the particle board makes the board more brittle and rigid. It is concluded that almond shell particles can be used in particle board production where brittleness and rigidness are desired though bending strength decreases with almond shell ratio. Also, by the physical tests, lower thickness swelling, and water absorption amount were detected with increasing almond shell ratio. In general, a decrease in mechanical properties with increasing almond shell particles is apparent, however, an improvement in mechanical properties occur with increasing board density. This finding is regarded as a favorable aspect in terms of application. In future work, image capture trials for microstructure examinations are planned and physical mechanisms that lead to the present test results are aimed to be investigated.
Latin American International Conference on Natural and Applied Sciences-II (Colombia, Bogotá), 2022
Almond is a common fruit/nut worldwide while its shell accounts for about half the weight of the ... more Almond is a common fruit/nut worldwide while its shell accounts for about half the weight of the fruit (shell weight is about equal to the edible part). Massive bulk shells are produced as a byproduct of almond production. The primary usage field of the shells is burning as a biomass solid fuel. However, there are applications where shells are used for filtering with or without carbonization, as additives to chemicals or cosmetics products. In the present report, almond shell is evaluated as a main constituent in organic particle board composites. A domestic type of almond shell bulk material was acquired and grinded to obtain granular form of it. Attained granular almond shells were mixed with dark oak chips with different volumetric ratios. The mixture was used in particle board production by means of heated compression molds and formaldehyde as binder. Several geometrical and operational parameters were also changed and tested, such as board thickness. Produced almond shell containing particle boards were tested and experimentally investigated for determining their thermal conductivities. The thermal conductivity tests were done in a branded test setup and facility, built in consistence with an international standard for determining thermal conductivity values. Tests were carried out for fixed temperature difference at different temperature levels, particle board densities, and almond shell volumetric rations in the particle boards. It is seen that density directly increases thermal conductivity while almond shell ratio has a changing effect on thermal conductivity based on particle board density. Also, thermal conductivity of the particle boards increases linearly with increasing temperature. Measured thermal conductivity values change between 0.07 and 0.19 W/m•K.
Abstract In this work, pin fin and plate heat sinks were investigated in terms of natural convect... more Abstract In this work, pin fin and plate heat sinks were investigated in terms of natural convection and radiation heat transfer by experimental means. One rectangular base plate and eight pin fin and plate heat sinks were manufactured particularly for this study. Eight different pin fin and plate heat sinks had four different pin fin numbers and hence pin fin spacings; and two different pin fin heights. Three different orientations of 0°, 90° and 180° were tested. Ten different constant heating rates were applied to heat sinks during tests, corresponding to Rayleigh number interval between 1 × 106 and 7 × 106. Heating powers were changed between 5 and 50 W by 5 W increments by means of DC electrical power source. All cases were compared with each other. Results were evaluated by calculating heat transfer indicators from experimental measurements, dependent Nusselt and Rayleigh numbers, and by drawing their corresponding graphics. It was detected that increasing pin fin number up to a threshold value increases thermal performance. After the threshold pin fin number, thermal convection coefficient decreases significantly. Up to the favourable highest pin fin number, the reason of thermal performance enhancement is due to increasing surface area without deteriorating thermal convection coefficient significantly. It is also seen that extended surface area by increasing number of pin fins partly compensates the reduction in thermal convection coefficient up to a level. However, increasing pin fin number further degrades heat transfer performance. Results show that the highest heat transfer is achieved by 121 × 40 pin fin and plate heat sink for all three orientation angles. The lowest heat transfer performance is realized by non-pinned plate. When plate orientation is considered, the highest heat transfer is achieved with upward facing orientation which has 0° orientation angle value, and the lowest heat transfer rate is realized with downward facing heat sink which has 180° orientation angle value. Therefore, it is concluded that inline pin fin and plate heat sinks are best used with upward orientation with optimum number of pins. Experimental dataset was analysed in terms of parametrical effects and accordingly empirical correlations expressions were composed and proposed.
Selcuk University Journal of Engineering Sciences, Sep 18, 2021
A 1.2-liter gasoline spark ignition internal combustion engine of a Renault Symbol sedan vehicle ... more A 1.2-liter gasoline spark ignition internal combustion engine of a Renault Symbol sedan vehicle was adapted to Liquid Petroleum Gas (LPG) fuel system in 2016. The LPG system utilizes LPG and gasoline fuels according to the operational needs. After modification, fuel consumption of the engine, fuel prices per liter, travelled distance in kilometers, dates and some additional data were recorded till November 2020. Collected data is processed for derivation of performance and economy indicators. Literature and web have been reviewed in order to find related works. Providing a solid application example of LPG conversion is aimed in this work. Also, a snapshot of fuel prices between 2016 and 2020 is being presented by graphical resolution. Approximately 12 to 15 times of initial investment cost has been returned till November 2020 by the LPG system. Also, slightly less CO2, i.e., 6%, has been emitted by means of the utilization of the system. Time resolution of the data is provided by graphics and integral data is also given. LPG conversion is found beneficial in terms of fuel cost. Also, viewed four years period does not reveal any performance problems in terms of energy spending per kilometer. However, engine additional amortization due to LPG system is not considered and this should be kept in mind.
Transient conjugated heat transfer in simultaneously developing turbulent flow is analyzed involv... more Transient conjugated heat transfer in simultaneously developing turbulent flow is analyzed involving two-dimensional wall and fluid axial conduction. A thick walled semi-infinite circular pipe which is considered initially isothermal and the problem is handled for steady, hydrodynamically and thermally developing flow with a sudden change in the outer wall temperature. The flow field and heat transfer are numerically investigated. Nondimensional continuity, Navier-Stokes and energy equations are solved by discretization using finite volumes method. Exponential discretization scheme is selected for the discretization of fluid side differential equations. Staggered grid system and SIMPLE algorithm are used in the flow solution. New computer software is developed for the numerical solution of the problem. Non-dimensional parameters that define the problem are determined as Reynolds number, Prandtl number, Peclet number, wall to fluid thickness ratio, wall to fluid thermal conductivity ratio, and wall to fluid thermal diffusivity ratio. Effects of each parameter on the heat transfer and flow characteristics are investigated in detail. Results change depending on all parameters. Reynolds number changing between 5×103 and 1×105 is the only parameter for flow solution. Hydrodynamic development length gets longer, directly proportional to Reynolds number and a characteristic velocity profile is attained at pipe axis. Peclet number that appears as a parameter in the energy equation for flow field during heat transfer solution can be investigated in a wide interval (1×102-2.5×105). Therefore, Peclet number is found to be the most important parameter that affects heat transfer. Heat transfer is affected by simultaneously developing flow. Exponential discretization scheme that has no known application in the solution of the problem gives result successfully.
Heat exchanger tubes are essential for separating fluids, especially for cross flow compact heat ... more Heat exchanger tubes are essential for separating fluids, especially for cross flow compact heat exchangers. However their geometries can cause vibration and hence noise, specifically when air is the case for external flow. Enhancing pneumatic performance by aerodynamic approaches is possible for such case and present study focuses on ellipse geometry and its orientations according to flow direction. 7 different orientation angles are selected for the experimental investigation; namely 0o, 22.5o, 30o, 45o, 60o, 67.5o and 90o. A Stereo PIV system of Dantec Dynamics was utilized which can capture 3000 single frame images for 6 seconds. Spatial data were used for post processing and results were prepared accordingly. Reynolds Number calculated according to the characteristic length of ellipse cylinders was 6000. With 30o orientation, flow structures around the ellipse cylinder becomes similar to flow structures around a bluff body. Flow separation from the leading edge of the ellipse cylinder increases with increasing angle of attack. Swirling flow in the separated region induces the drag force while increasing the lift forces. Vortex formations and vortex shedding lead to Karman vortex streets since the leading edge has a positive pressure gradient at upward direction according to the figure plane and negative pressure gradient at downward direction. This feature is unique for this special case of heat exchanger tube similarity and it is more likely seen in turbo machinery applications. Therefore spatial data of the wake is not axisymmetrical.
Well known geometries are essential in fluid mechanics due to the fact that flow around these geo... more Well known geometries are essential in fluid mechanics due to the fact that flow around these geometries can be foreseen relatively easily. In order to provide better scientific ground for the advanced research, researchers are still working on these geometries with new measurement techniques such as PIV method. In this study, three cylinders having different cross sections; namely short diameter circular cylinder (a=20mm), long diameter circular cylinder (D=65mm) and 3.25 aspect ratio of the elliptical cylinder were placed in an open water channel in order to investigate flow characteristics around them for the Reynolds number 6500. Experimental setup is presented in Figure 1. A Stereo PIV of Dantec Dynamics System was utilized for the velocity field measurement. Time-averaged streamline topology of the wake regions and vortex shedding from the flow separation regions are illustrated at the flow measurement plane. Figures displays time averaged streamwise velocity contours of a circular cylinder and an elliptic cylinder under uniform flow condition at Re=6500. The third velocity component contours for the measurement plane are presented. The elliptical cylinder acted as a streamline geometry comparing to the circular cylinder. Separation point was retarded for the elliptical cylinder and the wake was very narrower and shorter than the wake of the circular cylinder. Foci occur in the circular cylinder wake region and it occupies around 1.5D area in streamwise direction. These foci combine and form a stagnation point. On the other hand, the foci and stagnation point do not exist in the case of the elliptic cylinder case due to the diminished flow separation of the modified ellipse geometry. Circular cylinder wakes are identical each other independent as well known. The wake region of the elliptic cylinder is was smaller than the cylinder, which can provide better convection heat transfer coefficient around the body. The corresponding velocity contours also reflect the similar flow structure in geometrical shape. The obtained results can be used for the interpretation of real world applications and validation of various numerical works in heat transfers, building structure, heat exchangers, on/off-shore structure, military vehicles, bridge legs and sculpture.
Most of the major cities in the world are coastal cities. This is a natural outcome of the needs ... more Most of the major cities in the world are coastal cities. This is a natural outcome of the needs of human civilization. Some of the mentioned needs are transporting goods (shipping in literal means) and resources such as fish. On the other hand, wind and solar energy systems are usually built on arid land, away from settlements. Since there is an inverse relation between the size of a settlement and the aridness of a field, renewable energy systems, particularly wind and solar, are far from major settlements and industrial facilities. This creates and increases transfer/transmit and storage duties. Accordingly, additional costs arise. The additional costs and hardship undermine the transition to a carbon dioxide neutral circular sustainable life. Another thing about the location of renewables on land is that transmitting generated energy may not be possible at all. Consequently, offshore renewable energy systems are being studied and also applied. In the present work, we review the concurrent literature about offshore floating wind turbines, present an idea on them, and lay out basic equations for evaluating the idea based on economics and physics.
Arrays of offshore renewables are being studied by academia to justify them economically in real-... more Arrays of offshore renewables are being studied by academia to justify them economically in real-world applications by private sector entities. Offshore renewables' initial and levelized costs are significantly higher than their on-land counterparts. Therefore, energy density per unit area should be dramatically increased and/or cost lowered. However, concurrent knowledge of offshore industries other than renewable energy, such as fish farms, offshore oil platforms, and marine shipping, implies that lowering costs will not be sufficient. In order to increase the energy density per unit area, multiple offshore renewable energy systems relying on different physics should be combined in threedimensional space, thus creating an array. Also, systems and structures of other marine industries can be included in the concept to benefit from their readily present infrastructure. Such arrays are the subject of scientific and engineering investigation and assessment since hydrodynamics, aerodynamics, mechanics, and economics are involved. The topic is highly multidisciplinary. In this work, we reflect on the present situation and project future aspects.
To assess and forecast the operational performance of a modified car seat for thermal management ... more To assess and forecast the operational performance of a modified car seat for thermal management using an air conditioning system, statistical and machine learning (ML) models were used. By extending evaporator/condenser coils beneath the back and cushion surfaces of the car seat and using operational data on the HVAC system, such as seat temperature readings, an interval of operation was gathered. Using a data mining approach, statistically relevant factors and varying the compressor speed from 500 to 1600 rpm under various scenarios to model the system were selected. Utilizing key feature variables, our data-driven approach yielded predictions with favorable accuracy for the Coefficient of Performance (COP) of the HVAC system. By using the Akaike Information Criterion (AIC) to improve the Linear Regression (LR) model, the Root Mean Square Error (RMSE) dropped to 0.20, the Mean Absolute Error (MAE) dropped to 0.16, and the Coefficient of Determination (R 2) increased to 98 %. The Random Forest (RF) model, optimized with hyperparameters, demonstrated moderate predictive capability, with RMSE (0.52), MAE (0.37), and R 2 (94 %). Furthermore, polynomial feature augmentation, individual and combined predictor analysis, and iterative predictor combinations all improved predictive accuracy. Detailed information on the algorithms was given for the sake of other researchers.
Journal of the Faculty of Engineering and Architecture of Gazi University, 2024
Almond kernel, with a continuously increasing consumption, and is also important for our country,... more Almond kernel, with a continuously increasing consumption, and is also important for our country, is a valuable agricultural product. Its production yields the hard shell as a by-product. The shell and the kernel have approximately the same weight. However, the shell is usually burned, or occasionally ground for use in the cosmetic industry or filters. Almond shell is a porous, hard, lignocellulosic, and a renewable resource. Particleboard industry is considered for sustainable, higher value-added, and environmentally lower-impact use of this resource. For this purpose, a detailed literature review was conducted, and the reviewed studies were compiled and summarized. The literature review reveals numerous studies on the re-evaluation of shells of hard-shell nuts as materials for various industrial sectors. However, studies on almond shells are limited in number. After the literature review and conceptualization stages, particleboards with different densities and almond shell contents were produced using almond shell particles. The thermal conductivities of the boards were determined experimentally. The thermal conductivity value increases with the increase in board density. The almond shell content, however, exhibits different effects depending on the board densities. The smallest thermal conductivity value obtained in the study was 0.07 W/mꞏK, while the highest value was found to be 0.19 W/mꞏK. Although the study was conducted with a constant temperature difference, the thermal conductivity value increases with increasing temperature values.
Kahramanmaras Sutcu Imam University Journal of Engineering Sciences, 2023
In this study, the air flow resistance acting on scaled agricultural tractor models using a wind ... more In this study, the air flow resistance acting on scaled agricultural tractor models using a wind tunnel was determined experimentally. Tractor models have the same shape, but three different designs were tried on the operator platform section. These are the platform surrounded by the cab, the sunshade platform and the platform with the protection bar to protect the user in case of overturning. Thus, depending on the design of the user section, the air resistance changes that the tractors are exposed to in on-road transportation are determined experimentally for the first time. Tractor models used in the wind tunnel were prepared in a ratio of 1:13 according to geometric similarity principles. In wind tunnel tests, kinematic and dynamic similarity cannot be achieved, but Reynolds number independence can be obtained. A Reynolds number range was surveyed by performing experiments at different air velocities in the wind tunnel air flow rate range. In this range, the aerodynamic resistance forces acting on the models and the air flow-induced pressure distributions in the symmetry axis of the tractors were measured. Dimensionless aerodynamic drag coefficient and pressure coefficient values were calculated from the measurements obtained. According to the calculations, the use of the cabin increases the aerodynamic resistance in the range of 3-15%. While the percentage of resistance increase due to cabin usage is high at low speeds, it decreases at high speeds. As a result of the use of the cabin, the tractor front projection area perpendicular to the flow increases. However, the increase in aerodynamic drag is one order lower than the increase in the frontal projection area. Considering the benefits of cabin use in terms of occupational safety, it is understood that the increase in aerodynamic resistance due to cabin use is an acceptable cost. It is expected that the results of the study will contribute to the separation of energy consumption in on-road transportation with agricultural tractors.
Süleyman Demirel University Journal of Natural and Applied Sciences, 2023
In the trials of the present work, a double-axle trailer with a carrying capacity of 6 tons and a... more In the trials of the present work, a double-axle trailer with a carrying capacity of 6 tons and a hydraulically effective mechanical brake were used as a tractor towed car. There is a hydraulic brake system on each axle of the agricultural trailer. In order to separate the brake system on the axles from each other, a hydraulic mechanically controlled 2/2 directional control valve was mounted on both hydraulic brake system inlets. The study was carried out at constant speed (25 km h-1), on stabilized road conditions, with 4 different braking modes and 4 different trailer loads. On stabilized ground, the braking acceleration (deceleration) of the tractor (without trailer) is 5.51 m s-2. The braking acceleration of the combination is 2.15 m s-2 under the condition that the trailer's carrying capacity was 30% more loaded and without brakes, and the braking acceleration of the combination was 3.26 m s-2 when braking on both axles (4 wheels). The deceleration of the combination was above 3.5 m s-2 under the condition of braking on both axles at the rated load of the agricultural trailer, while it was below the standard value in other braking approaches.
Journal of Engineering Science and Technology, 2022
Data reduction and mathematical analysis are always an important part of heat transfer related st... more Data reduction and mathematical analysis are always an important part of heat transfer related studies. Regression curve (RCF) and Artificial Neural Network (ANN) fitting methods are used extensively and regarded as reliable tools for this purpose. ANN and RCF approaches are used to predict the Nusselt number (Nu), and Darcy friction factor (f) based upon a single input, namely, the Reynolds number (Re) varying from 2.3×10 3 to 52×10 3. Experimental results from a previous comprehensive study on forced thermal convection through a hexagonal duct was used to develop models and test the efficacy of the methods. Several ANN architectures, hyperparameter values and RCF functions were tested. Normalized and non-normalized datasets were considered. Models were compared with each other by means of statistical indicators. Therefore, this work is distinguished from the literature by its experimental data driven assessment and comparison between RCFs and ANNs. Additionally, single input and double output design is very scarce in the literature. The results show that the regression schemes based upon RCF are sufficient and accurate for predicting Nu and f, and the trend associated with the variation to Re is captured. The best single output ANN yields better accuracy; but the best double output ANN is unable to capture the expected trend between Re and the targeted responses. In terms of correlation coefficients, 0.98-0.99 is possible for RCFs and 0.99 for ANNs when normalization is done. Normalization becomes prominent as neuron number increases. As a conclusion, regression is preferred over ANN for a single input relationship between Nu and f to Re for hexagonal duct flow and heat transfer. An ANN's worth will only potentially be seen if more inputs; e.g., geometrical factors such as the aspect ratio, surface roughness, ambient temperature, duct material and relative wall thickness, among others, are included.
5. Internatinonal Conference on Materials Science, Mechanical and Automotive Engineerings and Technology (IMSMATEC’22), 2022
Production of almonds is increasing in a direct proportion to the increase in almond consumption ... more Production of almonds is increasing in a direct proportion to the increase in almond consumption of the world population. However, almond shells emerge as a byproduct since approximately half of the almond mass is the shell mass. Besides aiming financial gain, additional parameters should be considered due to sustainability issues and environmental concerns. Therefore, we are searching for alternative ways of almond shell utilization. Moisture value, porous structure, strength, and thermal conductivity of almond shells have a potential in respect of insulation purposes. In this work, particle boards from almond shell particles are investigated in terms of sound absorption and transmission properties. Experimental examination is utilized. In the measurements, transmission loss value can reach to 78 dB levels, making the boards a significant candidate for insulation purposes. Also, almond shell particle amount in the particle boards and variations in particle board densities greatly affect sound insulation properties of the boards.
New generation agricultural tractors contribute to transportation by increased travel speeds. The... more New generation agricultural tractors contribute to transportation by increased travel speeds. There is not any available aerodynamic data on authentic agricultural tractor form. On-road transportation by tractors is between 8 to 30% of their operational time. In this work, two agricultural tractors are modelled via computational fluid dynamics for nine different speeds to determine aerodynamic resistances. Corresponding speeds are 10 to 80 km/h with 10 km/h increments and additionally 5 km/h. Reynolds number changes between 1.6×105 and 2.98×106. The characteristic lengths are taken as the square root of the streamwise projected area of the tractor geometries. Aerodynamic forces exerted on the tractors change between 3 N to 746 N. The calculated drag coefficients are found as independent from Reynolds number and are 0.6 and 0.78 for the two different types of driver compartments. Constant speed travel scenarios are analysed. The approximated aerodynamic related fuel consumptions for ...
Karabakh III. International Congress of Applied Sciences "Year Of Shusha- 2022", 2022
Almond shell is a ligneous byproduct of almond fruit production process. This byproduct is usuall... more Almond shell is a ligneous byproduct of almond fruit production process. This byproduct is usually used as solid mass fuel. Almond shell as one of the lignocellulosic origin resources is thought to be evaluated as an alternative constituent in particle board production instead of burning it as a solid biomass fuel, in order to obtain more economical benefit. In this work, almond shells from almond fruit production process were acquired and they were grinded to make them suitable for particle board production. After the grinding process, particles sizes changing between 0.4 mm and 3.4 mm were obtained. Particle board production was realized by mixing those particles with black pine chips in different ratios. Urea formaldehyde was used as binder. Additionally, ammonium sulphate was utilized in order to harden the binder. Particle boards were obtained in laboratory conditions by proper compression pressure and temperature values for particle board production. Some particular physical and mechanical tests were done for the produced boards after climatization process. Density, thickness swelling, and water absorption amount values of the physical properties were calculated after submerging boards into water for 2 hours. In terms of mechanical properties, bending resistance and elasticity modulus, bending stress, and force values depending on the deflection were calculated. According to the obtained results, effects of almond shell and black pine particle ratios on physical and mechanical properties are examined. Additionally, mechanical, and physical properties of particle boards that were produced in different densities are investigated. At the end of the study, it is determined that increase in almond shell particle amount in the particle board makes the board more brittle and rigid. It is concluded that almond shell particles can be used in particle board production where brittleness and rigidness are desired though bending strength decreases with almond shell ratio. Also, by the physical tests, lower thickness swelling, and water absorption amount were detected with increasing almond shell ratio. In general, a decrease in mechanical properties with increasing almond shell particles is apparent, however, an improvement in mechanical properties occur with increasing board density. This finding is regarded as a favorable aspect in terms of application. In future work, image capture trials for microstructure examinations are planned and physical mechanisms that lead to the present test results are aimed to be investigated.
Latin American International Conference on Natural and Applied Sciences-II (Colombia, Bogotá), 2022
Almond is a common fruit/nut worldwide while its shell accounts for about half the weight of the ... more Almond is a common fruit/nut worldwide while its shell accounts for about half the weight of the fruit (shell weight is about equal to the edible part). Massive bulk shells are produced as a byproduct of almond production. The primary usage field of the shells is burning as a biomass solid fuel. However, there are applications where shells are used for filtering with or without carbonization, as additives to chemicals or cosmetics products. In the present report, almond shell is evaluated as a main constituent in organic particle board composites. A domestic type of almond shell bulk material was acquired and grinded to obtain granular form of it. Attained granular almond shells were mixed with dark oak chips with different volumetric ratios. The mixture was used in particle board production by means of heated compression molds and formaldehyde as binder. Several geometrical and operational parameters were also changed and tested, such as board thickness. Produced almond shell containing particle boards were tested and experimentally investigated for determining their thermal conductivities. The thermal conductivity tests were done in a branded test setup and facility, built in consistence with an international standard for determining thermal conductivity values. Tests were carried out for fixed temperature difference at different temperature levels, particle board densities, and almond shell volumetric rations in the particle boards. It is seen that density directly increases thermal conductivity while almond shell ratio has a changing effect on thermal conductivity based on particle board density. Also, thermal conductivity of the particle boards increases linearly with increasing temperature. Measured thermal conductivity values change between 0.07 and 0.19 W/m•K.
Abstract In this work, pin fin and plate heat sinks were investigated in terms of natural convect... more Abstract In this work, pin fin and plate heat sinks were investigated in terms of natural convection and radiation heat transfer by experimental means. One rectangular base plate and eight pin fin and plate heat sinks were manufactured particularly for this study. Eight different pin fin and plate heat sinks had four different pin fin numbers and hence pin fin spacings; and two different pin fin heights. Three different orientations of 0°, 90° and 180° were tested. Ten different constant heating rates were applied to heat sinks during tests, corresponding to Rayleigh number interval between 1 × 106 and 7 × 106. Heating powers were changed between 5 and 50 W by 5 W increments by means of DC electrical power source. All cases were compared with each other. Results were evaluated by calculating heat transfer indicators from experimental measurements, dependent Nusselt and Rayleigh numbers, and by drawing their corresponding graphics. It was detected that increasing pin fin number up to a threshold value increases thermal performance. After the threshold pin fin number, thermal convection coefficient decreases significantly. Up to the favourable highest pin fin number, the reason of thermal performance enhancement is due to increasing surface area without deteriorating thermal convection coefficient significantly. It is also seen that extended surface area by increasing number of pin fins partly compensates the reduction in thermal convection coefficient up to a level. However, increasing pin fin number further degrades heat transfer performance. Results show that the highest heat transfer is achieved by 121 × 40 pin fin and plate heat sink for all three orientation angles. The lowest heat transfer performance is realized by non-pinned plate. When plate orientation is considered, the highest heat transfer is achieved with upward facing orientation which has 0° orientation angle value, and the lowest heat transfer rate is realized with downward facing heat sink which has 180° orientation angle value. Therefore, it is concluded that inline pin fin and plate heat sinks are best used with upward orientation with optimum number of pins. Experimental dataset was analysed in terms of parametrical effects and accordingly empirical correlations expressions were composed and proposed.
Selcuk University Journal of Engineering Sciences, Sep 18, 2021
A 1.2-liter gasoline spark ignition internal combustion engine of a Renault Symbol sedan vehicle ... more A 1.2-liter gasoline spark ignition internal combustion engine of a Renault Symbol sedan vehicle was adapted to Liquid Petroleum Gas (LPG) fuel system in 2016. The LPG system utilizes LPG and gasoline fuels according to the operational needs. After modification, fuel consumption of the engine, fuel prices per liter, travelled distance in kilometers, dates and some additional data were recorded till November 2020. Collected data is processed for derivation of performance and economy indicators. Literature and web have been reviewed in order to find related works. Providing a solid application example of LPG conversion is aimed in this work. Also, a snapshot of fuel prices between 2016 and 2020 is being presented by graphical resolution. Approximately 12 to 15 times of initial investment cost has been returned till November 2020 by the LPG system. Also, slightly less CO2, i.e., 6%, has been emitted by means of the utilization of the system. Time resolution of the data is provided by graphics and integral data is also given. LPG conversion is found beneficial in terms of fuel cost. Also, viewed four years period does not reveal any performance problems in terms of energy spending per kilometer. However, engine additional amortization due to LPG system is not considered and this should be kept in mind.
Transient conjugated heat transfer in simultaneously developing turbulent flow is analyzed involv... more Transient conjugated heat transfer in simultaneously developing turbulent flow is analyzed involving two-dimensional wall and fluid axial conduction. A thick walled semi-infinite circular pipe which is considered initially isothermal and the problem is handled for steady, hydrodynamically and thermally developing flow with a sudden change in the outer wall temperature. The flow field and heat transfer are numerically investigated. Nondimensional continuity, Navier-Stokes and energy equations are solved by discretization using finite volumes method. Exponential discretization scheme is selected for the discretization of fluid side differential equations. Staggered grid system and SIMPLE algorithm are used in the flow solution. New computer software is developed for the numerical solution of the problem. Non-dimensional parameters that define the problem are determined as Reynolds number, Prandtl number, Peclet number, wall to fluid thickness ratio, wall to fluid thermal conductivity ratio, and wall to fluid thermal diffusivity ratio. Effects of each parameter on the heat transfer and flow characteristics are investigated in detail. Results change depending on all parameters. Reynolds number changing between 5×103 and 1×105 is the only parameter for flow solution. Hydrodynamic development length gets longer, directly proportional to Reynolds number and a characteristic velocity profile is attained at pipe axis. Peclet number that appears as a parameter in the energy equation for flow field during heat transfer solution can be investigated in a wide interval (1×102-2.5×105). Therefore, Peclet number is found to be the most important parameter that affects heat transfer. Heat transfer is affected by simultaneously developing flow. Exponential discretization scheme that has no known application in the solution of the problem gives result successfully.
Heat exchanger tubes are essential for separating fluids, especially for cross flow compact heat ... more Heat exchanger tubes are essential for separating fluids, especially for cross flow compact heat exchangers. However their geometries can cause vibration and hence noise, specifically when air is the case for external flow. Enhancing pneumatic performance by aerodynamic approaches is possible for such case and present study focuses on ellipse geometry and its orientations according to flow direction. 7 different orientation angles are selected for the experimental investigation; namely 0o, 22.5o, 30o, 45o, 60o, 67.5o and 90o. A Stereo PIV system of Dantec Dynamics was utilized which can capture 3000 single frame images for 6 seconds. Spatial data were used for post processing and results were prepared accordingly. Reynolds Number calculated according to the characteristic length of ellipse cylinders was 6000. With 30o orientation, flow structures around the ellipse cylinder becomes similar to flow structures around a bluff body. Flow separation from the leading edge of the ellipse cylinder increases with increasing angle of attack. Swirling flow in the separated region induces the drag force while increasing the lift forces. Vortex formations and vortex shedding lead to Karman vortex streets since the leading edge has a positive pressure gradient at upward direction according to the figure plane and negative pressure gradient at downward direction. This feature is unique for this special case of heat exchanger tube similarity and it is more likely seen in turbo machinery applications. Therefore spatial data of the wake is not axisymmetrical.
Well known geometries are essential in fluid mechanics due to the fact that flow around these geo... more Well known geometries are essential in fluid mechanics due to the fact that flow around these geometries can be foreseen relatively easily. In order to provide better scientific ground for the advanced research, researchers are still working on these geometries with new measurement techniques such as PIV method. In this study, three cylinders having different cross sections; namely short diameter circular cylinder (a=20mm), long diameter circular cylinder (D=65mm) and 3.25 aspect ratio of the elliptical cylinder were placed in an open water channel in order to investigate flow characteristics around them for the Reynolds number 6500. Experimental setup is presented in Figure 1. A Stereo PIV of Dantec Dynamics System was utilized for the velocity field measurement. Time-averaged streamline topology of the wake regions and vortex shedding from the flow separation regions are illustrated at the flow measurement plane. Figures displays time averaged streamwise velocity contours of a circular cylinder and an elliptic cylinder under uniform flow condition at Re=6500. The third velocity component contours for the measurement plane are presented. The elliptical cylinder acted as a streamline geometry comparing to the circular cylinder. Separation point was retarded for the elliptical cylinder and the wake was very narrower and shorter than the wake of the circular cylinder. Foci occur in the circular cylinder wake region and it occupies around 1.5D area in streamwise direction. These foci combine and form a stagnation point. On the other hand, the foci and stagnation point do not exist in the case of the elliptic cylinder case due to the diminished flow separation of the modified ellipse geometry. Circular cylinder wakes are identical each other independent as well known. The wake region of the elliptic cylinder is was smaller than the cylinder, which can provide better convection heat transfer coefficient around the body. The corresponding velocity contours also reflect the similar flow structure in geometrical shape. The obtained results can be used for the interpretation of real world applications and validation of various numerical works in heat transfers, building structure, heat exchangers, on/off-shore structure, military vehicles, bridge legs and sculpture.
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